Robust outlet plumbing for high power flow remote plasma source

ABSTRACT

The present invention generally includes a coupling between components. When igniting a plasma remote from a processing chamber, the reactive gas ions may travel to the processing chamber through numerous components. The reactive gas ions may be quite hot and cause the various components to become very hot and thus, the seals between apparatus components may fail. Therefore, it may be beneficial to cool any metallic components through which the reactive gas ions may travel. However, at the interface between the cooled metallic component and a ceramic component, the ceramic component may experience a temperature gradient sufficient to crack the ceramic material due to the heat of the reactive gas ions and the coolness of the metallic component. Therefore, extending a flange of the metallic component into the ceramic component may lessen the temperature gradient at the interface and reduce cracking of the ceramic component.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a divisional of U.S. patent application Ser. No.12/467,477 (APPM/013173), filed May 18, 2009, which claims benefit ofUnited States Provisional Patent Application Ser. No. 61/054,431(APPM/013173L), filed May 19, 2008, both of which are hereinincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

Embodiments of the present invention generally relate to a couplingbetween a metal cooling block and a ceramic gas tube.

2. Description of the Related Art

After numerous plasma processes, exposed components within theprocessing chamber may become coated with material that could flake offand contaminate further processes. In order to reduce contamination, theprocessing chamber and the exposed processing chamber parts may need tobe periodically cleaned. There is a need in the art for an apparatus andmethod to clean a processing chamber.

SUMMARY OF THE INVENTION

The present invention generally includes a coupling between components.When igniting a plasma remote from a processing chamber, the reactivegas ions may travel to the processing chamber through numerouscomponents. The reactive gas ions may be quite hot and cause the variouscomponents to become very hot and thus, the seals between apparatuscomponents may fail. Therefore, it may be beneficial to cool anymetallic components through which the reactive gas ions may travel.However, at the interface between the cooled metallic component and aceramic component, the ceramic component may experience a temperaturegradient sufficient to crack the ceramic material due to the heat of thereactive gas ions and the coolness of the metallic component. Therefore,extending a flange of the metallic component into the ceramic componentmay lessen the temperature gradient at the interface and reduce crackingof the ceramic component.

In one embodiment, an apparatus includes a remote plasma source, a gasfeedthrough tube, and a cooling block. The cooling block may be coupledbetween the remote plasma source and the gas feedthrough tube. Thecooling block may have a flange that extends into the interior of thegas feedthrough tube.

In another embodiment, a cooling block includes a cooling block bodyhaving an outside surface and one or more cooling channels within thebody, an inlet flange extending from the body at a first elevation, andan outlet flange extending from the body at a second elevation that isdifferent than the first elevation. The body may include a receivingsurface that surrounds the outlet flange. The receiving surface may berecessed from the outside surface.

In another embodiment, a gas feedthrough tube includes a gas feedthroughtube body having a first end, a second end, a first inner diameter, anda second inner diameter different than the first diameter.

In another embodiment, a method includes igniting a plasma in a remoteplasma source and flowing reactive gas ions from the remote plasmasource through a cooling block made of a first material and a gas tubemade of a second material different than the first material. The coolingblock may extend at least partially into the gas tube. The method mayalso include flowing a cooling fluid through the cooling block whileflowing the reactive gas ions therethrough.

BRIEF DESCRIPTION OF THE DRAWINGS

So that the manner in which the above recited features of the presentinvention can be understood in detail, a more particular description ofthe invention, briefly summarized above, may be had by reference toembodiments, some of which are illustrated in the appended drawings. Itis to be noted, however, that the appended drawings illustrate onlytypical embodiments of this invention and are therefore not to beconsidered limiting of its scope, for the invention may admit to otherequally effective embodiments.

FIG. 1 is a schematic cross sectional view of an apparatus 100 accordingto one embodiment of the invention.

FIG. 2A is a schematic cross sectional view of a gas tube 208 coupledbetween a cooling block 206 and an end block 202 leading to a processingchamber according to one embodiment of the invention.

FIG. 2B is a schematic cross sectional view of a portion of FIG. 2A.

To facilitate understanding, identical reference numerals have beenused, where possible, to designate identical elements that are common tothe figures. It is contemplated that elements and features of oneembodiment may be beneficially incorporated in other embodiments withoutfurther recitation.

DETAILED DESCRIPTION

The present invention generally includes a coupling between components.When igniting a plasma remote from a processing chamber, the reactivegas ions may travel to the processing chamber through numerouscomponents. The reactive gas ions may be quite hot and cause the variouscomponents to become very hot and thus, the seals between apparatuscomponents may fail. Therefore, it may be beneficial to cool anymetallic components through which the reactive gas ions may travel.However, at the interface between the cooled metallic component and aceramic component, the ceramic component may experience a temperaturegradient sufficient to crack the ceramic material due to the heat of thereactive gas ions and the coolness of the metallic component. Therefore,extending a flange of the metallic component into the ceramic componentmay lessen the temperature gradient at the interface and reduce crackingof the ceramic component.

The invention, as described below, may be practiced in a PECVD systemavailable from AKT, a subsidiary of Applied Materials, Inc., SantaClara, Calif. It is contemplated that the invention may be practiced inother plasma processing chambers, including those from othermanufacturers.

FIG. 1 is a schematic cross sectional view of an apparatus 100 accordingto one embodiment of the invention. The apparatus 100 comprises achamber body 102 enclosing a susceptor 104 upon which a substrate 106may be disposed. The apparatus 100 may be evacuated by a vacuum pump 108that is coupled with the chamber body 102. The substrate 106 may enterand exit the apparatus 100 through a slit valve opening 114 in thechamber body 102.

Processing gas may be introduced to the apparatus from a processing gassource 122. The gas may travel through a remote plasma source 124, acooling block 126, a resistor containing a gas tube 128, and an endblock 130 before entering the apparatus 100 through the backing plate116. A power source 120 may be coupled to the end block 130 to providepower to the showerhead 110 that is disposed in the apparatus 100opposite to the susceptor 104. The processing gas may enter theapparatus 100 through the backing plate 116 into a plenum 118 betweenthe gas distribution showerhead 110 and the backing plate 116. Theprocessing gas may then pass through gas passages 112 in the showerhead110 into the processing area 132. The resistor may be grounded to groundany current that travels from the power source 120 back in the directionof the gas source 122 and away from the backing plate 116.

The gas tube 128 may comprise an insulating material such as ceramicmaterial to prevent any electrical current from penetrating into the gastube 128 and igniting processing gas prior to entering the apparatus100. When cleaning the apparatus, cleaning gas is supplied from the gassource 122 and ignited into a plasma in the remote plasma source 124.The reactive gas ions from the plasma will be sent to the apparatus 100and be very hot which could lead to failure of any seals betweencomponents that are coupled together. Thus, the reactive gas ions maypass through a cooling block 126 before entering the gas tube 128 tocool the reactive gas ions. The cooling block 126 may comprise ametallic material having good heat conductance to permit a cooling fluidto draw heat from the plasma. Therefore, the body of the cooling block126 may have a lower temperature than the hot, reactive gas ions due tothe heat transfer.

The gas tube 128, which may comprise an insulating material, may becoupled to a surface of the cooling block 126. The gas tube 128 willalso have the hot, reactive gas ions flowing therethrough. Thus, the gastube 128 may experience a temperature gradient between the inside of thegas tube 128 through which the hot, reactive gas ions flow and theinterface with the cooling block 124. The temperature gradient may leadto cracking of the gas tube 128.

FIG. 2A is a schematic cross sectional view of a gas tube 208 coupledbetween a cooling block 206 and an end block 202 leading to a processingchamber according to one embodiment of the invention. The gas tube 208may be disposed in a resistor 204. The resistor 204 may have a metallicwire wrapped around the outside surface of the resistor 204 and coupledto the fastening mechanism 212 that couples the resistor 204 to the endblock 202. The wire may permit any electrical current flowing from thepower source that is coupled with the end block 202 to flow to ground.

The resistor 204 may comprise an electrically insulating material. Inone embodiment, the resistor 204 may comprise ceramic material. Theresistor 204 may have the gas tube 208 coupled thereto and extendingfrom one end to another end of the resistor 204. The resistor 204 may becoupled with the end block 202 by one or more fastening mechanisms 212.In one embodiment, the end block 202 may comprise a metallic material.In one embodiment, the end block 202 may comprise aluminum. In couplingthe resistor 204 to the end block 202, the gas tube 208 is also coupledto the end block 202 to permit the processing gas and reactive gas ions(from the remote plasma source) to flow through the gas tube 208 and theend block 202 to the processing chamber. The end block 202 may have aflange 216 that extends out from the body of the end block 202 and intothe gas tube 208. The end block 202 may have one or more coolingchannels 240 therein. Cooling fluid may be introduced to the end blockthrough a cooling fluid inlet 242. In one embodiment, the cooling fluidmay comprise air. In another embodiment, the cooling fluid may comprisewater. Thus, the walls of the gas tube 208 may enclose the flange 216 ofthe end block 202 when the gas tube 208 and end block 202 are coupledtogether.

The resistor 204 may also be coupled to the cooling block 206 using oneor more fastening mechanisms 214. In one embodiment, the cooling block206 may comprise a metallic material. In another embodiment, the coolingblock 206 may comprise aluminum. The cooling block 210 may have an inletflange 210 that couples to the remote plasma source. Cooling fluid mayenter the cooling block 206 through a cooling fluid inlet 226, flow incooling channels 236, and exit the cooling block 206 through a coolingfluid outlet 228. In one embodiment, the cooling fluid may comprisewater. In another embodiment, the cooling fluid may comprise air.Similar to the end block 202, the cooling block 206 may have a flange218 that extends from the body of the cooling block 206 and into the gastube 208 when the resistor 204 and cooling block 206 are coupledtogether. When in operation, the reactive gas ions may enter the coolingblock 206 through the flange 210, travel through the cooling block 206and out the flange 218 coupled to the gas tube 208. The reactive gasions may then travel through the gas tube 208 and the flange 216 of theend block 202. The reactive gas ions then travel through the end block202 and on to the processing chamber.

FIG. 2B is a schematic cross sectional view of a portion of FIG. 2A. Itshould be understood that while the coupling between the gas tube 208and the cooling block 206 is shown, the coupling between the gas tube208 and the end block 202 is substantially similar. In the embodimentshown in FIG. 2B, the gas tube 208 may extend into a recess 234 formedin the body of the cooling block 206. It is to be noted, however, therecess 234 may not be present and the gas tube 208 may not extend beyondthe body of the resistor 204. Thus, in one embodiment, the resistor 204and gas tube 208 are flush against the outside surface of the coolingblock 206 and have the same length.

The inner wall 222 of the gas tube 208 may have a first inside diametershown by arrow “A” and a second inside diameter shown by arrow “B” thatis greater than the first inside diameter. The larger diameter permitsthe flange 218 of the cooling block 206 to be inserted into the gas tube208. The flange 218 has an outer diameter shown by arrow “D” and aninside diameter shown by arrow “C”. The outside diameter of the flange218 may be smaller than the larger inside diameter of the gas tube 208to permit a gap 220 to be present between the flange 218 and the gastube 208. The gap 220 may be smaller than the plasma dark space andthus, reduce the likelihood of reactive gas ions that may have ignitedinto a plasma entering the gap 220. The gap 220 may reduce any particlegeneration that may occur if the flange 218 and the gas tube 208 rubtogether. The flange 218 may expand and contract due to the temperaturevariations between the hot, reactive gas ions for cleaning and theprocessing gas. Thus, the gap 220 may be sufficiently large to permitthe flange 218 to expand without rubbing the gas tube 208, butsufficiently small to reduce plasma formation within the gap 220.

The inside diameter of the flange 218 may be substantially equal to thesmallest inside diameter of the gas tube 208 (i.e., “A” may besubstantially equal to “C”). By having the diameters substantiallyequal, the flow of the processing gases may not be disturbed by anyabruptions in the gas tube 208 or flange 218.

By extending the flange 218 into the gas tube 208, the gas tube 208 mayhave a more gradual temperature gradient between the point 230 thatabuts the body of the cooling block 206 and the point 232 where theflange 218 ends. The flange 218, by extending out from the body of thecooling block 206, may have a temperature gradient. The end 234 of theflange 218 is furthest away from the body of the cooling block 206 mayhave a higher temperature when plasma flows through the cooling block206 as compared to the body of the cooling block 206 because the coolingfluid may not cool the flange 218 to the same extent as the body of thecooling block 206. Thus, the gas tube 208, due to it being adjacent tothe flange 218 having a temperature gradient, may have a temperaturegradient from the point 230 coupled to the body of the cooling block 206and the point 232 adjacent to the end 234 of the flange 234. Because ofthe flange 218, the temperature gradient between the point 230 adjacentthe body of the cooling block 206 and the point 232 adjacent the end 234of the flange 218 may be sufficiently low to reduce the potential forcracking of the gas tube 208.

By extending a flange of a cooling block into the gas tube, plasma maybe remotely generated and reactive gas ions delivered to the processingchamber for cleaning the processing chamber.

While the foregoing is directed to embodiments of the present invention,other and further embodiments of the invention may be devised withoutdeparting from the basic scope thereof, and the scope thereof isdetermined by the claims that follow.

1. A method, comprising: igniting a plasma in a remote plasma source;flowing reactive gas ions from the remote plasma source through acooling block having a flange made of a first material and a gas tubemade of a second material different than the first material, wherein thecooling block flange extends outwardly from the cooling block and iscontained at least partially within the gas tube; and flowing a coolingfluid through the cooling block while flowing the reactive gas ionstherethrough.
 2. The method of claim 1, wherein the first materialcomprises stainless steel.
 3. The method of claim 2, wherein the secondmaterial comprises ceramic.
 4. The method of claim 2, wherein the gastube has a first inner diameter and a second inner diameter differentthan the first inner diameter, and wherein the flange has a third innerdiameter substantially equal to the first inner diameter.
 5. The methodof claim 4, wherein the gas tube is coupled with an end block at an endopposite to the cooling block, and wherein the end block flange extendsat least partially into the gas tube.
 6. The method of claim 1, whereinthe second material comprises ceramic.
 7. The method of claim 6, whereinthe gas tube has a first inner diameter and a second inner diameterdifferent than the first inner diameter, and wherein the flange has athird inner diameter substantially equal to the first inner diameter. 8.The method of claim 7, wherein the gas tube is coupled with an end blockat an end opposite to the cooling block, and wherein the end blockflange extends at least partially into the gas tube.
 9. The method ofclaim 1, wherein the first material comprises aluminum.
 10. The methodof claim 9, wherein the second material comprises ceramic.
 11. Themethod of claim 10, wherein the gas tube has a first inner diameter anda second inner diameter different than the first inner diameter, andwherein the flange has a third inner diameter substantially equal to thefirst inner diameter.
 12. The method of claim 11, wherein the gas tubeis coupled with an end block at an end opposite to the cooling block,and wherein the end block flange extends at least partially into the gastube.
 13. The method of claim 1, wherein the gas tube is contained in aresistor
 14. The method of claim 13, wherein the resistor iselectrically coupled to a power source.
 15. The method of claim 14,wherein the resistor is electrically coupled to ground.
 16. The methodof claim 15, wherein the resistor comprises a ceramic material.
 17. Amethod, comprising: igniting a plasma in a remote plasma source; flowingthe reactive gas ions from the remote plasma source through a coolingblock made of a first material and a gas tube made of a second materialdifferent than the first material, wherein the cooling block extends atleast partially into the gas tube; and flowing a cooling fluid throughthe cooling block while flowing the reactive gas ions therethrough. 18.The method of claim 17, wherein the first material comprises stainlesssteel.
 19. The method of claim 18, wherein the second material comprisesceramic.
 20. The method of claim 17, wherein the second materialcomprises ceramic.